1. Field of the Invention
The present invention relates to a filter plug feeding apparatus used for manufacturing filter plugs for cigarettes and, more particularly, to a device for aligning the filter plugs themselves and the elements thereof.
2. Description of the Related Art
A typical example of a filter cigarette manufacturing machine or a so-called filter attachment is disclosed in U.S. Pat. No. 4,867,734. This conventional filter attachment is provided with a filter plug feeding apparatus, which forms dual filter plugs, and feed the formed filter plugs to grooved drums which constitute a transportation path of the filter attachment. The transportation path is used to transport pairs of cigarettes in the filter attachment.
More specifically, the feeding apparatus comprises a pair of hoppers, which are stored individually with charcoal filter rods and plain filter rods. The charcoal and plain filter rods delivered from the pair of hoppers are transferred toward the transportation path. In this process of transfer, various operations, such as cutting, separation, joining, grading, orientation, etc., are carried out. At the end of the transfer process, dual filter plugs are formed each having one plain plug and a pair of charcoal tips situated individually on the opposite sides thereof. Each dual filter plug formed in this manner is fed to the transportation path, and is located between a pair of cigarettes on this transportation path. Plain plugs and charcoal tips are obtained by cutting plain filter rods and charcoal filter rods, respectively.
In the filter attachment, thereafter, the pair of cigarettes and the dual filter plug are connected to one another by means of a tip paper piece, whereupon a double filter cigarette which is equivalent to two filter cigarettes is formed. The double filter cigarette is cut into two equal parts or filter cigarettes.
The formation of the aforementioned dual filter plug will be described more particularly. At the time when a pair of charcoal tips and one plain plug, which are the elements of a dual filter plug, are obtained by cutting, these charcoal tips and plain plug are placed coaxially, but they are positioned while being separated from each other in the axial direction.
For this reason, the filter plug feeding apparatus comprises an aligning device for making the paired charcoal tips and plain plug come closely into contact with each other by moving them in the axial direction, whereby a dual filter plug is formed.
The aligning device uses compressed air to move the paired charcoal tips and plain plug. The compressed air is blown from the side of one charcoal tip toward that charcoal tip, by which the charcoal tip is moved by receiving compressed air. As one charcoal tip is moved in this manner, it pushes the plain plug and the other charcoal tip in sequence, by which a dual filter plug in which these tips and plug come closely into contact with each other is formed.
Subsequently, the formed dual filter plug is collectively moved to a positioning guide by means of compressed air, so that the elements of dual filter plug is aligned at the side of the positioning guide.
In aligning the charcoal tips and plain plug, they are moved by being pushed by compressed air blown from the rear. Therefore, if the flow of air around the tips and plug is turbulent, the tip or the plug may sometimes rise during movement. The charcoal tip, which is an element of dual filter plug, rises more easily than the plain plug because of its short length.
If one element of filter plug rises, the formation of dual filter plug becomes incomplete, so that the dual filter plug cannot be supplied reliably from the feeding apparatus to the transportation path for the cigarettes. In such a situation, the manufacture of filter cigarette becomes impossible, and in the worst case, the operation of the filter attachment stops.
Moreover, since the positioning guide is fixedly disposed with respect to the feeding of the charcoal tips and plain plug, If the formed dual filter plug is incomplete, the dual filter plug is fed while one end thereof contacts slidingly with the positioning guide, which damages one end of dual filter plug.